Multi-segmented shaft

ABSTRACT

A multi-segmented shaft or dart configured for launching as a projectile using an atlatl or spear-thrower. In contrast to conventional darts, non-limiting exemplary embodiments of multi-segmented shafts or darts are disclosed. Such multi-segmented shafts can be de-coupled into a plurality of segments for ease of transport and storage. The plurality of segments can be detachably coupled into a dart that can be launched as a projectile using an atlatl or thrown as a spear.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/625,289 filed Feb. 1, 2018 which is herein incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

TECHNICAL FIELD

The instant disclosure relates to a multi-segmented shaft or dart configured for use with a spear-thrower, an atlatl, and similar instruments for launching a projectile.

BACKGROUND

An atlatl or spear-thrower is a tool for launching a dart or an elongated shaft using leverage to achieve greater velocity, increasing the travel distance, and/or increasing the force of the throw for greater penetration in a target. Prior art darts are relatively long and therefore are not easily transportable due to their lengths. Accordingly, there exists a need for a multi-segmented dart or shaft that can be easily “broken down” or disconnected or de-coupled into a plurality of segments for ease of transport and storage.

SUMMARY

A non-limiting exemplary embodiment of a shaft includes a distal segment, an intermediate segment, and a proximal segment, wherein each segment is defined at least in part by a distal end, a proximal end, and a spine. The shaft includes a spine defined at least in part by the spine of each segment, a distal end defined at least in part by the distal end of the distal segment, a proximal end defined at least in part by the proximal end of the proximal segment, and fletching disposed on the proximal segment proximate the proximal end of the shaft. The distal end of the shaft is configured for coupling with a projectile. The proximal end of the distal segment and the distal end of the intermediate segment include complementary configurations for detachable coupling. The proximal end of the intermediate segment and the distal end of the proximal segment include complementary configurations for detachable coupling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a non-limiting exemplary embodiment of an un-assembled multi-segmented shaft;

FIG. 1B illustrates the multi-segmented shaft of FIG. 1A in an assembled state;

FIG. 2 illustrates a non-limiting exemplary embodiment of another assembled multi-segmented shaft;

FIG. 3 illustrates a non-limiting exemplary embodiment of a distal section of a distal segment for the multi-segmented shaft of FIGS. 1A and 1B;

FIG. 4 illustrates a non-limiting exemplary embodiment of a distal section of a distal segment for the multi-segmented shaft of FIG. 2;

FIG. 5 illustrates a non-limiting exemplary embodiment of an atlatl for launching the multi-segmented shafts of FIGS. 1B and 2;

FIGS. 6A-6C illustrate non-limiting exemplary embodiments of various configurations of an exemplary segment for the multi-segmented shaft of FIGS. 1 and 2; and

FIG. 6D illustrates a non-limiting exemplary embodiment of a segment of the multi-segmented shaft of FIGS. 1 and 2.

DETAILED DESCRIPTION

One or more non-limiting embodiments are described herein with reference to the accompanying drawings, wherein like numerals designate like elements. It should be clearly understood that there is no intent, implied or otherwise, to limit the disclosure in any way, shape or form to the embodiments illustrated and described herein. While multiple exemplary embodiments are provided, variations thereof will become apparent or obvious to a person of ordinary skills. Accordingly, any and all variants for providing functionalities similar to those described herein are considered as being within the metes and bounds of the instant disclosure.

FIGS. 1A and 1B, respectively, illustrate a non-limiting exemplary embodiment of a multi-segmented shaft 10 in an un-assembled and assembled states. In some embodiments, the shaft 10 includes a distal segment 12, an intermediate segment 14, and a proximal segment 16. In certain embodiments, the distal segment 12 is defined at least in part by a distal end 18 and a proximal end 20; the intermediate segment 14 is defined at least in part by a distal end 22 and a proximal end 24; and the proximal segment 16 is defined at least in part by a distal end 26 and a proximal end 28.

In a non-limiting exemplary embodiment, the proximal end 20 of the distal segment 12 and the distal end 22 of the intermediate segment 14 have complementary features or configurations 30 and 32, respectively, for detachably coupling the distal and intermediate segments 12 and 14 to each other. Similarly, in certain embodiments, the proximal end 24 of the intermediate segment 14 and the distal end 26 of the proximal segment 16 have complementary features or configurations 34 and 36, respectively, for detachably coupling the intermediate and proximal segments 14 and 16 to each other. In a non-limiting exemplary embodiment, the complementary features on the abutting ends of the segments can be any of bayonet connector, N-connector, friction fit configuration, press fit configuration, threads, etc. This list of exemplary connector types should not be construed as being all encompassing or limiting. To the contrary, any type or form of configurations currently known or discovered in the future for detachably coupling two segments to each other are considered as being within the metes and bounds of this disclosure.

In a non-limiting exemplary embodiment, the shaft 10 is formed or constructed by detachably coupling the distal and intermediate segments 12 and 14 to each other at their respective proximal and distal ends 20 and 22; and detachably coupling the intermediate and proximal segments 14 and 16 to each other at their respective proximal and distal ends 24 and 26. Accordingly, the shaft 10 will have three detachably coupled segments, viz., distal, intermediate and proximal segments 12, 14 and 16. As such, the shaft 10 can be disassembled or “broken down” into its constituent parts when desired, as for example for transportation, storage, etc.

It should be noted that all the complementary features for detachably connecting the segments to each other do not have to be of the same type. In other words, the connector type or complementary features for detachably coupling the distal and intermediate segments 12 and 14 to each other does not have to be the same or identical as the connector type or complementary features for detachably coupling the intermediate and proximal segments 14 and 16 to each other.

In a non-limiting exemplary embodiment, it may be desirable to provide a shaft 10 that can be configured and re-configured as a two-segmented shaft (not shown) and a three-segmented shaft 10. Accordingly, in some embodiments, the same type of connector configurations may be provided for detachably coupling both the distal and intermediate segments 12 and 14 to each other and the intermediate and proximal segments 14 and 16 to each other. For instance, in some embodiments, both proximal ends 20 and 24 of the distal and intermediate segments 12 and 14 have same or similar connector configuration and a complementary connector configuration at both distal ends 22 and 26 of the intermediate and proximal segments 14 and 16. As such, the proximal end 20 of the distal segment 12 and the distal end 26 of the proximal segment 16 will have complementary configurations for detachably coupling the distal and proximal segments 12 and 16 to each other for constructing or forming a shaft having two segments (not shown).

The shaft formed or constructed as described herein, i.e., two-segmented shaft, three-segmented shaft 10, etc., will have a distal end 38 defined at least in part by the distal end 18 of the distal segment 12, and the shaft will have a proximal end 40 defined at least in part by the proximal end 28 of the proximal segment 16.

In a non-limiting exemplary embodiment, the distal end 38 of the shaft 10 is configured for coupling with or attaching a projectile point 42 such as, for example, a target point, an arrow head, a broadhead, etc., as are well known in the art. This list of exemplary projectile points 42 should not be construed as being all encompassing or limiting. To the contrary, any type or form of projectile points currently known or discovered in the future are considered as being within the metes and bounds of this disclosure.

In a non-limiting exemplary embodiment, the proximal end 40 of the shaft 10 is configured for coupling with or attaching a nock as is well known in the art. In another non-limiting exemplary embodiment, the proximal end 40 of the shaft 10 is configured as a proximal end of a crossbow bolt.

In a non-limiting exemplary embodiment, the shaft 10 includes fletching 44 disposed on at least a portion of the proximal segment 16 proximate the proximal end 40 of the shaft 10. A fletching, as is well known in the art, provides aerodynamic stabilization during flight.

FIG. 5 illustrates a non-limiting exemplary embodiment of an atlatl or spear-thrower 46 for launching a dart (or projectile) such as for example the multi-segmented shaft 10. Since atlatls are well known in the art, details such as their design, configuration, use, etc., is considered not necessary for this disclosure. In some embodiments, the atlatl 46 includes a spur 48 disposed at a proximal end 50 and a rest 52 at a distal end 54. In certain embodiments, the spur 48 is configured for receiving or retaining the proximal end 40 of the shaft 10. In some embodiments of the shaft 10, the proximal end 40 includes a hollow configured for receiving the spur 48 prior to launch. Alternate or additional configurations for receiving or retaining or otherwise cooperating with the proximal end 40 of the shaft 10 are well known in the art and therefore are not repeated herein. In some embodiments, the rest 52 includes a retainer or holder 56 on which at least a portion 58 of the proximal segment 16 of the shaft 10 is retained or held prior to launching the shaft 10. In certain embodiments, the retainer or holder 56 is one of the two components of a hook-and-loop fastener or a hook-and-pile fastener or a touch fastener with the complementary component 60 disposed on the portion 58 of the proximal segment 16 of the shaft 10. One such exemplary fastener is the well-known VELCRO® brand fastener. In some embodiments, the rest 52 includes a depression or cut or similar configuration for receiving the portion 58 of the proximal segment 16 of the shaft 10.

In a non-limiting exemplary embodiment, each of the distal segment 12, the intermediate segment 14, and the proximal segment 16 has a “spine”. “Spine” is an industry-standard measurement of the stiffness of an arrow shaft. For measuring spine, the shaft is supported at two points which are separated by a distance of 28 inches, and a 1.94-pound weight is applied at a mid-point of the shaft. The distance the shaft deflects relative to the horizontal is defined as the “spine.” An arrow must have certain spine characteristics, depending on its length and the draw weight of the archery bow, to achieve proper flight. Generally, the heavier the draw weight the stiffer the spine (i.e., less deflection) must be. Lighter arrow shafts have the principal advantage of higher velocities when launched from the same bow. Such higher velocities result in a flatter arrow trajectory. The practical advantage of flatter trajectory is that a misjudgment by an archer of the range to a target has less effect on the point of impact. When spine is discussed herein, “stiffer” spine means less arrow deflection (i.e., a smaller numeric value), and “weaker” spine means greater arrow deflection (i.e., a larger numeric value). Thus, the terms “less spine” and “stiffer spine” have the same meaning throughout. In a similar manner, the terms “more spine” and “weaker spine” have the same meaning throughout.

Accordingly, the fully assembled multi-segmented shaft 10 will have a spine. In some embodiments, the spine of the shaft 10 will be defined at least in part by the spine of the individual segments, viz., the distal segment 12, the intermediate segment 14, and the proximal segment 16, that form the shaft 10.

In a non-limiting exemplary embodiment, the spine of at least one of the distal, intermediate and proximal segments 12, 14 and 16 is substantially similar to the spine of at least one of the other two segments. In some embodiments, the spine of the distal and proximal segments 12 and 16 are substantially similar. In certain embodiments, the spine of at least one of the distal, intermediate and proximal segments 12, 14 and 16 is substantially different from the spine of at least one of the other two segments. In some embodiments, the spine of the distal and proximal segments 12 and 16 are substantially different. In certain embodiments, the spine of the intermediate segment 14 is less than the spine of the distal and proximal segments 12 and 16. In some embodiments, the spine of the intermediate segment 14 is greater than the spine of the distal and proximal segments 12 and 16.

The spine of each individual segment, an arrow shaft, and similar implements is affected by their dimensions, weight, material, physical characteristics, geometric configurations, etc. Parameters that have at least a partial affect on the spine include, and are not limited to the shaft or segment being tubular on the outside and whether it is a hollow, solid, or partially hollow cylinder. If it is a hollow or partially hollow cylinder, then the inside diameter, and consequently the wall thickness, will affect the spine. For instance, the spine of a shaft or segment having a substantially constant inside diameter along its longitudinal extent will be different from the spine of a shaft or segment having a varying inside diameter between its two ends, i.e., the distal and proximal ends. In this regard, the inside diameter can increase or decrease proximally from the distal end, i.e., from the distal end to the proximal end. In a non-limiting exemplary embodiment, the inside diameter of the shaft or segment might decrease proximally from the distal end to a pre-determined location and thereafter increase proximally to the proximal end. Accordingly, the inside diameter at the pre-determined location will be smaller or minimum relative to other locations along the longitudinal extent of the shaft or segment. The minimum inside diameter can be located proximate the mid-point of the shaft or segment and/or can be of a pre-determined portion or section along the longitudinal extent of the shaft or segment. Consequently, the wall thickness and the weight of the shaft or segment will also be affected by the manner in which the inside diameter varies along the longitudinal extent of the shaft or segment.

While it is desirable to provide a shaft or segment that is tubular on the outside, the interior of the shaft or segment can be of any geometric shape including, and not limited to, circular, rectangular, square, triangular, polygonal, parallelogram, etc. In such instances of non-circular internal geometry, the “inside diameter” as described and applied or used herein will be defined at least in part by the effective diameter or the equivalent diameter or the hydraulic diameter of the geometric shape in the interior of the shaft or segment.

In a non-limiting exemplary embodiment, one or more of the distal, intermediate and proximal segments 12, 14 and 16 is tubular such as, for example, a hollow cylinder, defined at least in part by an inside diameter, an outside diameter, and a wall defined at least in part by an outer surface and an inner surface. In some embodiments, the inside diameter of at least one of the distal, intermediate and proximal segments 12, 14 and 16 is substantially similar to the inside diameter of at least one of the other two segments. In certain embodiments, the inside diameter of at least one of the distal, intermediate and proximal segments 12, 14 and 16 is substantially different from the inside diameter of at least one of the other two segments. In some embodiments, the inside diameter of the intermediate segment 14 is less than the inside diameter of each of the distal and proximal segments 12 and 16. In certain embodiments, the inside diameter of at least one of the distal, intermediate and proximal segments 12, 14 and 16 varies between its distal and proximal ends. In some embodiments, the inside diameter of the intermediate segment 14 decreases proximally from the distal end 22, attains a minimum, and thereafter increases proximally to the proximal end 24. In certain embodiments, the minimum inside diameter of the intermediate segment 14 is at a location proximate a mid-point between the distal and proximal ends 22 and 24 of the intermediate segment 14. In some embodiments, the inside diameter at the proximal end 20 of the distal segment 12 and the inside diameter at the distal end 22 of the intermediate segment 14 are substantially equal. In certain embodiments, the inside diameter at the proximal end 24 of the intermediate segment 14 and the inside diameter at the distal end 26 of the proximal segment 16 are substantially equal. In some embodiments, the outside diameter at the proximal end 20 of the distal segment 12 and an outside diameter at the distal end 22 of the intermediate segment 14 are substantially equal. In certain embodiments, the outside diameter at the proximal end 24 of the intermediate segment 14 and the outside diameter at the distal end 26 of the proximal segment 16 are substantially equal.

In view of the foregoing, FIGS. 6A-6C illustrate non-limiting exemplary embodiments of various configurations of a tubular section 70 of the multi-segmented shaft 10. In some embodiments, the tubular section 70 represents a portion of the distal segment 12 and/or 68. In certain embodiments, the tubular section 70 represents a portion of the intermediate segment 14. In some embodiments, the tubular section 70 represents a portion of the proximal segment 16. In other words, the tubular section 70 is a portion of any one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16.

FIG. 6A illustrates a non-limiting exemplary embodiment of a tubular section 70 a defined at least in part by a wall 72 a, and having substantially constant inside and outside diameters 74 a and 76 a, respectively, and substantially constant wall thickness 78 a along at least a portion of its longitudinal extent. In some embodiments, the inside and outside diameters 74 a and 76 a and the wall thickness 78 a are substantially constant along the entire longitudinal extent of any one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16.

FIG. 6B illustrates a non-limiting exemplary embodiment of a tubular section 70 b defined at least in part by a wall 72 b and having a substantially constant inside diameter 74 b along at least a portion of its longitudinal extent. In some embodiments, the outside diameter 76 b and the wall thickness 78 b decrease along at least a portion of its longitudinal extent. In certain embodiments, the entire longitudinal extent of the one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16 has a substantially constant inside diameter 74 b, and decreasing outside diameter 76 b and wall thickness 78 b. In some embodiments, the outside diameter 76 b and the wall thickness 78 b decrease proximally, i.e., in the proximal direction towards the proximal end. In certain embodiments, the outside diameter 76 b and the wall thickness 78 b decrease distally, i.e., in the distal direction towards the distal end.

FIG. 6C illustrates a non-limiting exemplary embodiment of a tubular section 70 c defined at least in part by a wall 72 c and having a substantially constant outside diameter 76 c along at least a portion of its longitudinal extent. In some embodiments, the inside diameter 74 c and the wall thickness 78 c decrease along at least a portion of its longitudinal extent. In certain embodiments, the entire longitudinal extent of the one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16 has a substantially constant outside diameter 76 c, and decreasing inside diameter 74 c and wall thickness 78 c. In some embodiments, the inside diameter 74 c and the wall thickness 78 c decrease proximally, i.e., in the proximal direction towards the proximal end. In certain embodiments, the inside diameter 74 c and the wall thickness 78 c decrease distally, i.e., in the distal direction towards the distal end.

FIG. 6D illustrates a non-limiting exemplary embodiment of a tubular section 70 d defined at least in part by a wall 72 d and having a substantially constant outside diameter 76 d along at least a portion of its longitudinal extent. In some embodiments, the inside diameter 74 d′ decreases distally (or proximally), attains a minimum inside diameter 74 d″ proximate a location 80, and thereafter increases to either the original inside diameter 74 d′ or a different inside diameter. Consequentially, the wall thickness 78 d′ increases distally (or proximally), attains a maximum wall thickness 78 d″ proximate the location of the minimum inside diameter 74 d″, and thereafter decreases in tandem with the varying or changing inside diameter 74 d. In some embodiments, the inside diameter 74 d and the wall thickness 78 d vary or change as described along at least a portion of the longitudinal extent of the one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16. In certain embodiments, the inside diameter 74 d and the wall thickness 78 d vary or change as described along the entire longitudinal extent of the one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16. While the varying or changing inside diameter 74 d and wall thickness 78 d are illustrated in a parabolic geometry (or U-shaped), this should not be construed as a requirement or a limitation. Any and all geometric shape or configuration are considered as being within the metes and bounds of the instant disclosure. For instance, the change in the inside diameter and, consequently, the wall thickness can be a step-change or triangular-shaped or any other geometry.

Additionally or in the alternative any one or more of the inside diameter, the outside diameter, and the wall thickness need not extend over or circumscribe the entirety of their respective inner/outer circumference or perimeter. Shaft 10 and/or one or more of the distal, intermediate, and proximal segments 12/68, 14, and 16 wherein the inside diameter, the outside diameter, and the wall thickness vary or change over only a portion of their respective inner/outer circumference or perimeter are considered as being within the metes and bounds of the instant disclosure.

The term “diameter” is used in a general sense and should not be construed as being limiting to the diameter of a circular or tubular object such as, for example, a cylinder or tube and the like. As described herein above, the term “diameter” as referenced herein includes the effective diameter or the equivalent diameter or the hydraulic diameter of the geometric shape in the interior of the shaft or segment.

In some embodiments, the shaft 10 has a substantially smooth transition whereat two adjacent segments are detachably coupled. In certain embodiments, the shaft 10 has a substantially uniform outside surface whereat two adjacent segments are detachably coupled. As will be apparent to one skilled in the art, the smooth transition of the outside surface between detachably coupled adjacent segments is desirable for increasing the aerodynamic efficiency, for example decreasing the drag, of the shaft 10 during flight.

In some embodiments, the outside diameter 62 of the shaft 10 is substantially constant along its entire longitudinal extent. In certain embodiments, the outside diameter 62 of the shaft 10 varies along its entire longitudinal extent. In some embodiments, the outside diameter 62 of the intermediate and proximal segments 14 and 16 is substantially constant along their respective longitudinal extent, and the outside diameter 64 of the distal segment 12 varies along its longitudinal extent. In some embodiments, the outside diameter 64 may vary along the entire longitudinal extent of the distal segment 12. In certain embodiments, the outside diameter 64 may vary along only a distal section 66 of the distal segment 12. FIG. 3 illustrates a non-limiting exemplary embodiment of the distal segment 12 wherein the outside diameter 64 increases proximally from the distal end 18. FIG. 4 illustrates a non-limiting exemplary embodiment of the distal segment 16 wherein the outside diameter 62 is substantially constant along its entire longitudinal extent. As will be apparent to one of ordinary skill in the art, the outside diameters at the proximal end 20 of the distal segment 12 and at the distal end 22 of the intermediate segment 14 should be substantially same for ensuring a smooth transition when the segments 12 and 14 are detachably coupled.

It should be noted that the description herein as it relates to the distal end 18 of the distal segment 12, and consequently the distal end 38 of the shaft 10, applies equally to the distal end 66 of the distal segment 68. Furthermore, except for the differences pertaining to the outside diameters, the distal segments 12 and 68 are substantially the same in all other aspects. Accordingly, the description herein as it relates to all such “other aspects” of the distal segment 12 applies equally to the distal segment 68.

While the disclosure herein above describes only one intermediate segment 14, this should not be construed as a requirement or a limitation. Shafts with multiple, i.e., more than one, intermediate segments are considered as being within the metes and bounds of the instant disclosure. Of course, for detachably coupling two intermediate segments, the adjacent intermediate segments must have complimentary configurations as described here with reference to the distal, intermediate, and proximal segments 12, 14, and 16.

In a non-limiting exemplary embodiment, the plurality of segments for the multi-segmented shaft are configured for automatic or semi-automatic attachment such as, for example, shock corded tent poles, collapsible walking canes, etc. In some embodiments, an elastic “shock cord” extends through adjacent segments and/or through multiple segments.

While the description herein references or pertains to a multi-sectional shaft or dart that can launched as a projectile using an atlatl or spear-thrower, it should be apparent that the disclosure equally pertains to a multi-segmented spear that can be launched by hand. Accordingly, the disclosure should not be construed as limiting or applicable only as described herein. To the contrary, other uses or applications of the disclosed multi-segmented projectile such as, but not limited to, an arrow shaft, a crossbow bolt, a spear, a dart, etc., are considered as being within the metes and bounds of the disclosure.

In view thereof, modified and/or alternate configurations of the embodiments described herein may become apparent or obvious to one of ordinary skill. All such variations are considered as being within the metes and bounds of the instant disclosure. For instance, while reference may have been made to particular feature(s) and/or function(s), the disclosure is considered to also encompass any and all equivalents providing functionalities similar to those disclosed herein with reference to the accompanying drawings. Accordingly, the spirit, scope and intent of the instant disclosure is to embrace all such variations. Consequently, the metes and bounds of the instant disclosure are defined by the appended claims and any and all equivalents thereof. 

What is claimed is:
 1. A shaft, comprising: a distal segment, an intermediate segment, and a proximal segment, each comprising: a distal end; a proximal end; and a spine; a spine defined at least in part by the spine of each segment; a distal end defined at least in part by the distal end of the distal segment; a proximal end defined at least in part by the proximal end of the proximal segment; and fletching disposed on the proximal segment proximate the proximal end of the shaft; wherein, the distal end of the shaft is configured for coupling with a projectile point; the proximal end of the distal segment and the distal end of the intermediate segment comprise complementary configurations for detachable coupling; and the proximal end of the intermediate segment and the distal end of the proximal segment comprise complementary configurations for detachable coupling.
 2. The shaft of claim 1, wherein the spine of at least one segment is substantially similar to the spine of at least one of the other two segments.
 3. The shaft of claim 2, wherein the spine of the distal and proximal segments are substantially similar.
 4. The shaft of claim 1, wherein the spine of at least one segment is substantially different from the spine of at least one of the other two segments.
 5. The shaft of claim 4, wherein the spine of the distal and proximal segments are substantially different.
 6. The shaft of claim 1, wherein the spine of the intermediate segment is less than the spine of the distal and proximal segments.
 7. The shaft of claim 1, wherein the spine of the intermediate segment is greater than the spine of the distal and proximal segments.
 8. The shaft of claim 1, wherein one or more of the segments is tubular.
 9. The shaft of claim 8, wherein an inside diameter of at least one of the segments is substantially similar to an inside diameter of at least one of the other two segments.
 10. The shaft of claim 8, wherein an inside diameter of at least one of the segments is substantially different from an inside diameter of at least one of the other two segments.
 11. The shaft of claim 8, wherein an inside diameter of the intermediate segment is less than an inside diameter of each of the distal and proximal segments.
 12. The shaft of claim 8, wherein an inside diameter of at least one of the segments varies between its distal and proximal ends.
 13. The shaft of claim 12, wherein the inside diameter of the intermediate segment decreases distally from the proximal end, attains a minimum, and thereafter increases distally to the distal end.
 14. The shaft of claim 13, wherein the minimum inside diameter is at a location proximate a mid-point between the distal and proximal ends of the intermediate segment.
 15. The shaft of claim 8, wherein an inside diameter at the proximal end of the distal segment and an inside diameter at the distal end of the intermediate segment are substantially equal.
 16. The shaft of claim 8, wherein an inside diameter at the proximal end of the intermediate segment and an inside diameter at the distal end of the proximal segment are substantially equal.
 17. The shaft of claim 8, wherein an outside diameter at the proximal end of the distal segment and an outside diameter at the distal end of the intermediate segment are substantially equal.
 18. The shaft of claim 8, wherein an outside diameter at the proximal end of the intermediate segment and an outside diameter at the distal end of the proximal segment are substantially equal.
 19. The shaft of claim 8, wherein an outside diameter of the distal segment increases proximally from the distal end thereof
 20. The shaft of claim 8, wherein an outside diameter of the distal segment is substantially constant along its entire longitudinal extent.
 21. The shaft of claim 8, wherein the spine of each of the distal, intermediate, and proximal segments is defined at least in part by at least one of an inside diameter, an outside diameter, wall thickness, weight, and composition of the material of the segment.
 22. The shaft of claim 1, comprising a substantially smooth transition in an outside surface between the detachably coupled adjacent segments.
 23. The shaft of claim 1, wherein an outside surface of the shaft whereat adjacent segments are detachably coupled is substantially uniform. 